NicoN Posted May 22, 2019 Report Share Posted May 22, 2019 Since ages our CDT-Indication does not work. These days, I removed the sensor from the cable to the combined-instrument. At least, the indicator seems to be fine. The hand goes to maximum deflection with the contacts shorted and is zero with the contacts open. With a potentiometer I can reach any position. From this, I would think it is a NTC-type sensor The sensor has unlimited resistence. Of course that is in cold condition. I do not see a short between one of the cables and the sensor housing. Looking for a replacement, I have seen that this particular sensor is sold out at LASAR. By mail we gort the information (not from Mooney), that CDT, TIT and EGT have the same sensors. Indeed, at LASAR they all start with A002*, but the CDT-sensor is named A002-CDT, while a TIT/EGT-sesonsor is named A002C-30. Also our sensors look different. EGT/TIT has metal skins on the cables while CDT is only white plastic. Also, the expexted temperatures differ pretty much to be the same sensor type for all. Does someone have more information or an alternative source for this sensor? Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 22, 2019 Report Share Posted May 22, 2019 I have seen this question arise before, Nico... I think anyone with a JPI 900 has simply gone with a TC in that location... The range that TIT has to sit in causes it to be a bit more expensive... but technically it is a TC of the same type... See if you can contact Dan at Lasar and ask him what everyone is using now. The web site might not be telling the detail that you want. In the CDT location a good TC will last nearly forever... compared to the confluence of several exhaust pipes entering the turbo... Do you have an intercooler with that? DeltaT across the intercooler has got to be interesting as well... same TC there? Stuff I have read about on MS... fuzzy memories at best... I don’t even have a turbo...nevermind an inter-cooler... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
N231BN Posted May 22, 2019 Report Share Posted May 22, 2019 I don't remember who makes them for Lasar but I think they are the only source. You are correct in identifying the probe as a thermistor. When I purchased my 231 someone had tried to replace it with a TC. Quote Link to comment Share on other sites More sharing options...
NicoN Posted May 22, 2019 Author Report Share Posted May 22, 2019 @carusoam: Yes, I started a topic long time ago. I am a bit confused at the moment: From one point, CDT seems to be an airworthinenss-item.Nevertheless, no-one noticed it or took care. on the other hand, the service manual say, CDT is not critical unless you go high and with high power. Hmm - what now ? The factory sensor does not do anythinig. We have a EDM830 with nearly all sensors installed, except - yes, CDT-option! To install it is still on the list, together with the alarm light for the EDM. But this still makes the 830 not a legal replacement for the factory gauges. So, I was happy to find, I have a working instrument with a simple sensor which is easy to replace. Some people diagnosed the CDT/TIT-Instrument is being damaged. 1 Quote Link to comment Share on other sites More sharing options...
kortopates Posted May 22, 2019 Report Share Posted May 22, 2019 Did you check with KS Avionics? http://www.ksavionics.com/products/catalog_ksa_probes.phpSent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 23, 2019 Report Share Posted May 23, 2019 Also, Nico... The answer to how important the sensor/gauge is... Is it primary? The answer is found in your POH... known as the MEL... The POH will list equipment required for VFR, IFR, and day/night. Check the POH for the MELs... See if there is a check Mark next to it.... It may be important like the ship’s single CHT gauge or less important like an EGT gauge... typically the TIT is going to be important for maintaining the health of the turbo... Intake to the engine temp is also important to avoid detonation... So... if you don’t have CDT or something to tell what the temp of the air entering the engine is. It is probably on the MEL... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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